The life of a creator is one of continuous, iterative improvements.

Very Zen. Much philosophy. And you know, so's life in general.

A while ago, I noticed issues where my video and audio exports had audible clicks where there was none in the timeline. With each re-render they would be in a slightly different spot. More infuriatingly, I didn't notice them because I only played back the video exports at 1.5x speed and not the audio as well, and at a faster speed the clicks wouldn't usually come through[1].

Things were going fine, but I was doing audio specific work, and I noticed the exports sounded *off*. Not as bad as a cooked mp3, but sort of flat-sounding with compression-like artefacting at the edges. I couldn't hear the problem in my source files and the files I was getting out of Izotope RX in pre-processing so there was something definitely happening in DaVinci Resolve.

Good news, I worked out how to fix the problem. Bad news, I don't have the time to go back through my old content to reprocess everything again, so I have to live with the older releases having defects unless there's a solid justification for me to dedicate those hours to do it.

## Step 1. Check your source

Don't waste time mucking around in Resolve. GIGO (Garbage In, Garbage Out) is key here. Make sure the problems you're hearing aren't present in your source files.

## Step 2. Use wavs (if applicable)

For those using separate audio tracks, apparently, Resolve will devote precious processing power to converting audio into wavs on the fly if that's not the format they're imported in. Unless you can throw more hardware at the problem, convert your audio to wav first.

## Step 3. Pre-process your audio files before importing them into DaVinci Resolve

Resolve has some nice audio processing tools in Fairlight, but I find third-party presets can increase rendering time, and adds extra processing load that could cause artefacts. Instead of using the presets for RX in Resolve, I'll process the files in the RX standalone app, export as wav, and use those instead.

**Additional:** I download the separate audio only track from [riverside.fm](https://riverside.fm/?via=steampoweredshow) to process for this reason. There aren't sync issues either as long as you don't use the constant bitrate video.

## Step 4. Set audio export settings

Update your audio export settings to be:

* Format: QuickTime
* Codec: LinearPCM
* Sample rate: 48000
* Bit depth: 24

`QuickTime` with `LinearPCM` is the combination most commonly suggested by Resolve users for general audio problems. When the Bit depth is lower than `24`, I get the flat compression issues. `24` clears that up.

![DaVinci Resolve file export settings](audio-export-settings.png)

## Step 5. Slow down the render speed

Slowing down the render speed will help with both click and artefacting problems. With my hardware, on free DaVinci Resolve with CPU rendering I needed `50` to get rid of the clicks. In paid DaVinci Resolve Studio using my graphics card, I could get away with `75`.

![DaVinci Resolve file export settings](file-export-settings.png)

For those on free and not great hardware, I'm sorry, your render time is going to suck. But at least you won't have these problems in your exports anymore.


---

[1] Also super annoyed that I can't replace the video on YouTube without losing stats, but you have to pick your battles.


Reduce artefacts in audio exports from DaVinci Resolve.

Improve DaVinci Resolve Audio Export Quality

To be quite honest, the summary of this post is that I'm just too old for this shit. Gone are the days where I had all the time in the world to faff around with customising builds to my heart's content.

![Source: [Reddit](https://www.reddit.com/r/howtonotgiveafuck/comments/78pe0r/behold_the_field_in_which_i_grow_my_fucks/)](barren.jpg)

## The problems

The matter with [configuring audio over Xrdp](/2020/12/23/configure-audio-over-xrdp-centos) was one hurdle. Annoying, but not a show-stopper.

But other things that cropped up included:

### Limited export formats on DaVinci Resolve

I couldn't export H.264 MP4 with AAC audio which is what I was using on macOS. I had to use LinearPCM which would fail to successfully upload on more than one platform I needed it on. I tried a variety of other combinations of audio and video to no avail. Some combinations even failed to play back in QuickTime or VLC let alone get anywhere online.

The only option in these cases was to transcode them with `ffmpeg` or Handbrake after the initial render. But, why.

### Audio over Xrdp was fragile

Even after all that setup, things just didn't quite work, but only sometimes? Audio would cut out or not be in sync over remote. If I wanted to switch to working from the box directly, audio would not transfer back. Restarting services sometimes worked, but most of the time I'd have to restart the box entirely. I'm sure if I had figured out the right combination of services to restart it would have done the thing, but then I'd have to restart the services every time I needed to do that. Again, why.

### Laggy interface

This one perplexes me. I noticed the DaVinci Resolve UI was particularly laggy. I thought perhaps it was because I was using it remotely, but even on local it was janky if marginally better. Resources weren't being unusually taxed, other things were working fine, it was just kind of rubbish even when it was the only thing actively running. It was sort of tolerable in the way you're alright with the sound of dripping water for a little while, but not for extended periods of editing. No workaround.

## The last straw

But really the big one was the codec issue. I was not going to sit through two extended periods of rendering just to get the file in the format I wanted. One render in DaVinci Resolve run already took 1.5-2 times the length of the video to be rendered on its own let alone what I'd have to do with it using `ffmpeg` or Handbrake. Just, no.

Given I am comfortable and familiar with macOS, I did briefly entertain the idea of a hackintosh. But, just, no. If my field of fucks was barren for CentOS, it would not be less barren for a hackintosh.

And this is why I tapped out and went to Windows.


How do I regret thee, let me count the ways.

CentOS regret

MDX on GatsbyJS nests JSX components in paragraph tags which can produce invalid HTML so you end up with invalid HTML resembling:

```html
<p>
	<div class="jsx-component">...</div>
</p>
```

When using Markdown tables, it can also leave extra whitespace that can produce HTML syntax warnings. Not showstopping, but annoying all the same.

Create this plugin in your `./plugins` directory and add it to the end of your `gatsbyRemarkPlugins` in `gatsby-config.js`.

<Gist id="c5321b66ef8afabd6f0fdf67055aabc8" />


MDX wraps components with paragraph tags and can add extra whitespace in tables which produce invalid HTML. This GatsbyJS plugin cleans up the markup.

Clean-up Extraneous Paragraph Tags and Table Whitespace in MDX on GatsbyJS

For [STEAM Powered](https://steampoweredshow.com) Facebook videos and YouTube allow you to attach an SRT file for captions. However, Twitter and Instagram do not and captions need to be baked-in.

Use this bash script create new videos with the SRT captions baked-in. The script needs to be run in the directory that contains video files with their corresponding SRT files (with the `.en_US` language suffix). New videos with the captions baked-in will be created in the same directory.

<Gist id="97e0b54ef35929bf05a3dcf1ae316ff5" />


How to create baked-in captions in videos using srt files and ffmpeg.

Bake-in SRT Captions into Videos Using ffmpeg

If you have multiple timelines that need to be exported with the same settings:

<Callout type="accent" icon="⚠️">
This won't work if you have captions.
</Callout>

1. Select the timelines
2. Context menu → "Create New Timeline Using Selected Clips"
3. Deliver → Custom
4. Set Location for output
5. Under Video, select "Individual Clips"
6. Under File, Filename uses "Source name" (filename will be timeline name)
7. Other settings as needed.

If your video size is non-standard, you will need to set the size to Custom to match the source content, and Crop to Fit.


Exporting multiple timelines at one in DaVinci Resolve.

Batch Export Timelines

These are the steps I took to configure Xrdp on CentOS to allow me to hear audio over Microsoft Remote Desktop on OSX. YMMV.

Install the [pulseaudio-module-xrdp](https://github.com/neutrinolabs/pulseaudio-module-xrdp) module using the instructions based on those provided by [neutrinolabs](https://github.com/neutrinolabs/pulseaudio-module-xrdp/wiki/README) with modifications that I needed to make it work on my install.

## CentOS 8

### **Prerequisites**

Xrdp needs to have been installed.

Some build tools and package development tools are required. Make sure you install the tools.

```bash
yum groupinstall "Development Tools"
yum install rpmdevtools yum-utils
rpmdev-setuptree
```

### **Prepare & build**

Install pulseaudio and requisite packages to build pulseaudio.

**Note:** The *powertools* and *okay* repos needed to be added for `yum-builddep`. The *okay* repo was current at time of writing, you may need to update this.

```bash
yum install pulseaudio pulseaudio-libs pulseaudio-libs-devel
yum config-manager --set-enabled powertools
rpm -ivh http://repo.okay.com.mx/centos/8/x86_64/release/okay-release-1-3.el8.noarch.rpm?
yum-builddep pulseaudio
```

Fetch the pulseaudio source and extract. You'll see `~/rpmbuild/BUILD/`

```bash
yumdownloader --source pulseaudio
rpm --install pulseaudio*.src.rpm
```

If the source download fails due to being unavailable, manually download the source rpm. Use the name that it says it failed to find and have a dig around for the source. I found the version I needed here, but you can dig further up the tree to see if you can find yours:

[https://vault.centos.org/8.3.2011/AppStream/Source/SPackages/pulseaudio-13.99.1-1.el8.src.rpm](https://vault.centos.org/8.3.2011/AppStream/Source/SPackages/pulseaudio-13.99.1-1.el8.src.rpm)

When executing `rpm --install` you might see:

```bash
warning: user mockbuild does not exist - using root
warning: group mockbuild does not exist - using root
```

It's okay, these are just warnings, it probably worked. You'll find out shortly.

Build the pulseaudio source. In this phase, pulseaudio is not necessarily needed to be built but configured however there's no way to do only configure.

```bash
rpmbuild -bb --noclean ~/rpmbuild/SPECS/pulseaudio.spec
```

Finally, let's build Xrdp source / sink modules. You'll have two .so files `module-xrdp-sink.so` and `module-xrdp-source.so`.

```bash
git clone https://github.com/neutrinolabs/pulseaudio-module-xrdp.git
cd pulseaudio-module-xrdp
./bootstrap && ./configure PULSE_DIR=~/rpmbuild/BUILD/pulseaudio-[YOUR VERSION]
make
```

## **Install**

Just `make install` should install built modules to the correct directory.

You can confirm if the modules properly installed by following command:

```bash
ls $(pkg-config --variable=modlibexecdir libpulse)
```

If you can see lots of `module-*.so` and `module-xrdp-sink.so`, `module-xrdp-source.so`, PulseAudio modules should be properly built and installed.

`module-xrdp-sink.la` and `module-xrdp-source.so` may be installed to the target directory, these files are not necessary and you can remove them safely.

Enjoy!

## **See if it works**

To see if it works, run `pavumeter` in the xrdp session. Playback any YouTube video in Firefox. You'll see "Showing signal levels of **xrdp sink**" and volume meter moving.

## Troubleshooting

* Audio pitch is lower than it should be

    Modify `/etc/pulse/daemon.conf`, uncomment or add `default-sample-rate = 44100`

* Choppy audio

    No actual solution set, unfortunately. YouTube playback is choppy, but straight audio playback is fine.


## Additional Sources

* [https://okay.network/blog-news/rpm-repositories-for-centos-6-and-7.html](https://okay.network/blog-news/rpm-repositories-for-centos-6-and-7.html)


Configuring Xrdp on CentOS for use over Microsoft Remote Desktop.

Configure audio over Xrdp on CentOS

tl;dr: I need to generate my own SRT files for my videos because Facebook Creator Studio makes me angry.

Long: [Backstory](/rail-yard/video-captions).

## Requirements

- python
- [ffmpeg](https://www.ffmpeg.org/)
- Google Cloud API Key with the Speech to Text product enabled. ([instructions](https://cloud.google.com/speech-to-text/docs/quickstart-client-libraries))

More details for installation and usage in the script below.

## Notes

Default GCS only works for videos no longer than 60 seconds, and the script will only send the first 60 seconds of video to accommodate this. Modifications are required to use GCS for longer videos[1].

I find the `video` transcription model more accurate than the `default`, but `video` is a premium model if that matters to you. I still need to make corrections, but far fewer than Facebook's auto-captioning feature.

For bin length, I've set it to a default of 3 seconds with a line break of 37 characters[2].

```text
1
00:00:05,100 --> 00:00:07,500
Big Bang Theory thank you. So
especially in that
```

<Gist id="abbabb693f37d49ccbd9348178c5963b" />

---

[1] See [https://towardsdatascience.com/how-to-use-google-speech-to-text-api-to-transcribe-long-audio-files-1c886f4eb3e9](https://towardsdatascience.com/how-to-use-google-speech-to-text-api-to-transcribe-long-audio-files-1c886f4eb3e9)

[2] 3 seconds seems to come up a bit, and the first subtitle style-guide I found is from the [BBC](https://bbc.github.io/subtitle-guidelines/) and I saw 37 characters on there because of teletext. For online it's based on percentage of screen-width and at that point I realised close enough is good enough. Got better numbers? Let me know.


Using Google Cloud Services Speech to Text to generate SRT files from short videos.

Generate SRT files with Google Cloud Services


<Callout type="warning" icon="⚠️">

Decided I have better things to do with my time and picked up [Izotope RX Standard](https://www.izotope.com/en/shop/rx-8-standard.html) when it was about 50% off. Leaving this here for posterity. That said, the EQ stuff in Step 4 I still use.

</Callout>

Getting a decent mic has made a big difference to the sound quality of my local audio recordings[1] but I've been remiss in the audio aspect of post-production. In part because I have no idea what I'm doing and was spending more time than I had available faffing around with dials and knobs I didn't fully understand.

But I appear to have developed some electrical or signal interference in my recordings and while Garbage-In-Garbage-Out is absolutely a thing, I needed to figure out how to eliminate or at the very least minimise the annoying sound that to me sounds like I have a giant fan next to me, but apparently only I can hear[2].

Don't use wireless headphones for audio work. I also had issues with wired Apple earbuds. I had better luck with in-ear earbuds with the soft silicon tips, but circumaural (encloses ear) headsets were best. Learned this the hard way.

So, audio clean-up crash-course time. Will flesh this out more as I learn. Will use audio n00b terms that are in all likelihood wrong. But if you're using this as a guide, firstly, gods help you, secondly, this has got to be slightly better than the other tutorials I saw which were effectively "Dick around with the dials and levels until it sounds right, *et voila*."

### Step 1: Master Volume

I raised/lowered the individual speech track sliders so that Master sits mostly on the mid-to-lower end of 10-15 (yellow).

### Step 2: Noise Gate

Apply a Noise Gate. This defaults Threshold -35dB but may have to drop this some to avoid clipping too much voice. For the issue that I was having, -38dB is what worked. I set Attack to 1ms as that gives me better edges.[3] There was also some fiddling with Release but honestly, I can't tell what I'm listening for here. This was set to about 78.

This cleans up where there is no speech, and leaves it sounding a little stilted because of the aforementioned edges where the noise is under the speech.

You can also add Compression here by setting the Threshold to just below the peak. Didn't need or do much because of Step 1. Compression will clean up the extremes.

### Step 3: Noise Reduction

Apply the Noise Reduction plugin. I used the same settings as for the Noise Gate, jacked Smoothing up to 2. Wet/Dry (raw vs processed) defaults to 80% but I fiddled between 80-100% until it sounded okay. 80% was about right. I found the Auto speech mode produced more clipping, so I used Manual then hit Learn over a decent section of speech. Don't know if this is what you're meant to do. Will figure it out later.

This cleans up the noise behind the speech and makes it sound less clipped/stilted.

### Step 4: EQ (optional)

Activate bands 1 and 6 and set to curves up and curves down respectively. Set 2 and 5 to the round one.

Working from 2-5 (or 5-2) one at a time (not sure if there's a reason you should go one way or the other) max out Gain, playback speech while increasing the Frequency dial until the audio sounds the most whistley or the most annoying. Drag Gain back down to between -2 to -10dB. Stop when it sounds alright. Going too far down makes you sound like you're in a hole.

Repeat for other bands.

For the noise issue, once 1-3 was done, EQ didn't do too much.

### Step 5: Save changes as a preset

Follow this guide to save the setting for later use.

- Step 6: Properly learn audio editing or something

## Extra Things

- Some sections of laughter or exclamation can be quite loud. In Fairlight, select Normalise Audio Levels from the clip context menu. This also allows the volume for these to be more consistently set than from dragging the volume control in Cut or the volume line elsewhere.

---

[1] Although frankly almost anything is better compared to using my earbuds.

[2] And if I can hear it, good chance that other people younger than me can, too. So you know, probably most of my target audience.

[3] I have no idea if 'clipping' or 'edges' are even words I should be using in the audio context, but if I treat sound post like image processing it makes sense to me.


The technical details behind the creation of STEAM Powered.

Fairlight Audio Clean-Up


I use markers in DaVinci Resolve to annotate videos for show notes and navigation links in YouTube video descriptions.

![YouTube timeline](timeline.png)

To output the marker info as an EDL, activate the timeline whose markers you want to output, then in the **Media** tab, right-click on the timeline, select **Timelines** &rarr; **Export** &rarr; **Timeline Markers to EDL...** and save the EDL file.

<Callout type="warning" icon="⚠️">

If the timeline isn't open, the <strong>Timeline Markers to EDL</strong> menu item will not be available.

</Callout>

![DaVinci Resolve Screenshot](screenshot.png)

Then, use the following python script to output the marker info in the format:

```text
[00:00:00] Marker name
```

<Gist id="fe15ae724b1cc92bb88f7b6c7e5ac274" />


Use DaVinci Resolve marker EDLs to create timelines that can be used in show notes and YouTube timelines.

Convert DaVinci Resolve Markers to YouTube Compatible Timelines


I make short video clips for promoting [STEAM Powered](https://steampoweredshow.com) on social media by taking sections of the main timeline and pasting them into new timelines. This copies the raw track only and doesn't include any Fairlight settings I may have applied to the track in the original timeline.

To replicate track settings across multiple timelines, you'll need to use the **Fairlight** &rarr; **Presets Library...** menu option.

![DaVinci Resolve Menu](menu.png)

Select **Global track presets** option from the **Filter by** dropdown. You can target whatever you want from the list, but I needed Effects, EQ, and dB to be replicated, so global it was.

Select the track you want the settings copied from, then **Save New**.

![DaVinci Resolve Presets](presets.png)

To apply the preset, go to the target timeline, select the preset and the track and click on **Apply**.


Replicate Fairlight settings when using the same track on multiple timelines.

10 posts tagged “steam-powered”